textproduct: Albany

WHAT HAS CHANGED

Expected storm track has shifted even slightly farther north for late Friday into early Saturday morning, most likely resulting in moderate snowfall extending north through the I-90 corridor with heavy snow in the southeast Catskills, mid Hudson Valley and northwest Connecticut. A Winter Storm Warning has now been issued for areas where heavy snow is expected, with a Winter Weather Advisory for areas where moderate snowfall is expected.

KEY MESSAGES

1. Moderate to heavy snow late Friday afternoon into early Saturday morning, with the most impactful snowfall along and south of I-90. Heaviest snow expected in the southeast Catskills, mid Hudson Valley and northwest Connecticut.

2. Precipitation develops by Sunday evening and may continue into Monday morning, likely beginning as a wintry mix (including freezing rain) before potentially ending as plain rain or rain/snow mix in higher elevations by Monday morning.

3. Much colder with windy conditions and lake effect snow beginning Tuesday.

DISCUSSION

KEY MESSAGE 1...

No significant weather hazards today through Fri morning. Northwest winds will increase and gust between 25-40 mph this afternoon into this evening behind a cold front, with scattered snow showers mainly in mountain areas north of Albany. It will also turn colder tonight, with lows ranging from -5F in the Adirondacks to lower 10s in the mid Hudson Valley. Feels-like temperatures range from around -15F to 5F.

The cold air mass will remain in place on Fri, as high pressure retreats NE across Quebec and a progressive short wave trough, very similar to a "ridge-roller" type disturbance which produces summertime MCS activity, approaches from the Great Lakes. The associated surface cyclone is expected to track E/SE across the Ohio Valley and mid Atlantic regions from Fri afternoon through early Sat morning. A swath of snow positioned to the north of the cyclone will produce a moderate to locally heavy snowfall from around the I-90 corridor south. Slightly sloped F-Gen maximized in the 800-700 mb layer should result in some mesoscale banding with fairly significant snowfall rates and SLR slightly above climo at 13:1 to 15:1, although there is low confidence in exact locations.

The expected storm track has shifted even slightly farther north in the blended guidance. Confidence is greatest for 6-7"+ snowfall across the eastern Catskills, mid Hudson Valley and NW CT, where a Winter Storm Warning has been issued. Moderate snowfall is expected farther north to the I-90 corridor, where amounts of 3-6" are now expected. Farther north and east, amounts of generally 2-4 inches are now expected. It should be noted that there remains lower confidence farther north and east, and if trends continue to shift north, some advisories and even warnings may need to be adjusted northward later in time.

Mesoscale banding could lead to heavy snowfall rates Friday evening within the warning area, with 12Z HREFs suggesting some hourly snowfall rates of 1-2"/hour (probs for > 1"/hour ~60-80" between 6 and 10 PM, and probs for >2"/hour are 20-40% during same time period). Farther north, snowfall rates could reach/slightly exceed 1"/hour as far north as I-90 between 6-10 PM. This will be in association with greatest surge of warm advection and potential mesoscale banding.

Temperatures will be very cold Friday and will likely drop several degrees when the snow starts due to wet bulb effects. Many areas will likely fall into/through the teens, perhaps even some lower teens, while the snow is occurring, so it will make snow removal efforts particularly challenging on area roadways, likely leading to very slippery travel conditions with snow covered roads.

KEY MESSAGE 2...

Precipitation from the next system is already expected to move in by Sun evening, as a deepening cyclone tracks from the central Great Lakes into Quebec from Sun evening through Mon afternoon. The system's warm front will bring over-running precip Sun night, but with shallow low level cold/initially dry air in place there will likely be a wintry mix to start (mainly sleet/freezing rain), which will linger longest across the favored higher terrain and sheltered areas north of Albany into Mon morning.

There is a moderate/high potential for at least some ice in many areas with NBM 24 probs for > 0.01" ice ending 7 AM Monday of 40-90%+ (greatest in higher terrain and portions of the eastern Mohawk Valley and upper Hudson Valley). Similar NBM probs for > 0.10 ice are mainly limited to the mountain areas at 10-40%. Cold ground surfaces leading into the precipitation event will increase the potential for hazardous travel conditions on untreated ground/road surfaces.

As the cyclone tracks into Quebec on Mon, warming would result in wintry mix changing to rain in lower elevations with a rain/snow mix in the higher terrain ahead of the system's cold front. 24-hr NBM probs for > 0.50" liquid equivalent ending 7 PM Monday are 60-90%, and 40-70% for > 1.00", although there remains uncertainty on placement of greatest amounts.

Temperatures could reach/exceed 40 in some areas south of I-90 Monday before the system's cold front moves through in the afternoon. Gusty winds and some snow showers may then follow in the wake of the cold front Monday night, especially for areas north/west of Albany.

KEY MESSAGE 3...

Cold front will be past the region late Monday night and Tuesday morning, with surface low pressure just to our north. This low is progged to continue strengthening with plentiful CVA and divergence aloft, setting up a robust northwest to southeast oriented pressure gradient across the region. Add in 40-50 kt winds aloft and surface CAA promoting low-level mixing, and we are set up nicely for potential advisory level (45-55 mph) wind gusts across much of the area. Latest NBM probs have jump on board with this potential, with at least a 50-80% chance of wind gusts greater than or equal to 45 mph mainly across higher elevations in the Berkshires, Catskills and southern ADKs. Probabilities decrease across the Capital District and Upper Hudson Valley, though it is worth noting these chances have been trending upward in latest model runs.

Given the strong CAA, will also need to watch potential for lake effect/upslope snow showers. Being this far our, confidence on exact amounts and locations of heaviest snows are low. Temperatures are also favored to be well below normal, which is in line with the latest CPC 6-10 day outlook.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

Through 00z Saturday...VFR conditions at all terminals as of 6:00 PM EST, which should prevail through most if not all of the TAF period. A few mid-level clouds between 3500-4500 ft this evening should diminish by 06Z, with increasing high clouds after that through the remainder of the night and tomorrow morning. Clouds thicken and lower tomorrow afternoon ahead of the next approaching storm system. The start time of the snow associated with this next system will likely be shortly before 00z Sat at ALB/POU and shortly after 00z at GFL/PSF. Once snow begins vsbys will quickly drop to MVFR and then IFR. NW winds will at 10-15 kt with gusts of 20-25 kt diminish to 5-10 kt and veer to the N/NE after 06z, but some lingering gusts to around 15 kt continue through daybreak at POU/PSF. By tomorrow afternoon, winds diminish to 5 kt or less.

Outlook...

Friday Night: High Operational Impact. Definite SN. Saturday: Moderate Operational Impact. Chance of SN. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Low Operational Impact. NO SIG WX. Sunday Night: High Operational Impact. Definite RA...FZRA. Monday: High Operational Impact. Breezy. Definite RA...SN. Monday Night: Moderate Operational Impact. Windy With Gusts To 33 kts. Chance of RA...SN. Tuesday: Moderate Operational Impact. Windy With Gusts To 31 kts. Slight Chance of SN.

ALY WATCHES/WARNINGS/ADVISORIES

CT...Winter Storm Warning from 4 PM Friday to 1 PM EST Saturday for CTZ001-013. NY...Winter Storm Warning from 4 PM Friday to 1 PM EST Saturday for NYZ058-059-063>066. Winter Weather Advisory from 4 PM Friday to 1 PM EST Saturday for NYZ038>040-047>054-060-061. MA...Winter Weather Advisory from 4 PM Friday to 1 PM EST Saturday for MAZ001-025. VT...None.